1. Field of the Invention
The present invention relates to a device for compensating a weak cooling or overcooling for a cooling chamber of a refrigerator, and in particular to an improved device for compensating a weak cooling or overcooling for a cooling chamber of a refrigerator which can compensate a weak cooling/overcooling by using a single input terminal of a microprocessor in order to simplify a circuit and decrease a cost when compensating the weak cooling/overcooling by connecting a plurality of switches to a plurality of input terminals of the microprocessor.
2. Description of the Background Art
A conventional weak cooling/overcooling compensation device for a cooling chamber will now be explained with reference to the accompanying drawings. FIG. 1 illustrates a structure of the conventional weak cooling/overcooling compensation device for the cooling chamber. As shown therein, four input terminals of a microprocessor performing the weak cooling/overcooling compensation according to variation of an input signal are respectively connected to four option pins, and the four option pins are respectively connected to four resistances. The option pin is a kind of switch which can be easily cut, and thus performs an open operation of the switch. The operation of the conventional weak cooling/overcooling compensation device for the cooling chamber will now be described with reference to FIG. 2.
FIG. 2 is a temperature compensation table of the conventional weak cooling/overcooling compensation device for the cooling chamber. In case the weak cooling/overcooling takes place in the cooling chamber (not shown), as shown in the temperature compensation table of FIG. 2, the weak cooling/overcooling is compensated by cutting the necessary option pin. As depicted in FIG. 1, a voltage is not applied to the input terminal connected to the option pin which is not cut, and a voltage of 5V is applied to the input terminal connected to the option pin which is cut. The microprocessor senses an input variation resulting from cutting of the option pins, and performs the weak cooling/overcooling temperature compensation. For example, in the case that the weak cooling takes place in the cooling chamber and thus a temperature of the cooling chamber needs to be compensated by xe2x88x921xc2x0 C., as shown in the temperature compensation table of FIG. 2, the first option pin OP1 is cut, and the other option pins OP2xcx9cOP4 are not cut (option pins are all connected when shipped from the factory). Accordingly, the input values inputted to first to fourth input terminals of the microprocessor are varied to 5V, 0V, 0V and 0V, respectively. The microprocessor receiving the input values compensates for the temperature by xe2x88x921xc2x0 C. In the same manner, as shown in the temperature compensation table of FIG. 2, when only the second option pin is cut, the input values inputted to the first to fourth input terminals of the microprocessor are varied respectively to 0V, 5V, 0V and 0V. Thus, the microprocessor compensates for the temperature by xe2x88x921xc2x0 C.
When the overcooling takes place in the cooling chamber, the resultant temperature compensation will now be explained. In order to increase the temperature of true cooling chamber when the overcooling is generated therein (for instance, in case a temperature must be increased by +2xc2x0 C.), as shown in the temperature compensation table of FIG. 2, the third and fourth option pins are cut, and the first and second option pins are not cut. In this case, the input values inputted to the first to fourth input terminals of the microprocessor are varied to 0V, 0V, 5V and 5V, respectively. Accordingly, the microprocessor compensates for the temperature by +2xc2x0 C. However, when the temperature compensation is performed, the number of the temperatures to be compensated may be increased. In addition, a spare option pin may be necessary, which results in the increased number of the option pins.
In the conventional art, as the number of the option pins to be cut in order to compensate the weak cooling/overcooling is increased, the number of the input terminals of the microprocessor is also increased. As a result, a substrate size and a fabrication cost are increased.
It is therefore an object of the present invention to provide a weak cooling/overcooling compensation device for a cooling chamber which can decrease a substrate size and a fabrication cost by reducing input terminals of a microprocessor into one.
In order to achieve the above-described object of the present invention, there is provided a weak cooling/overcooling compensation device for a cooling chamber, including: a plurality of resistances connected in series between the power and ground; a plurality of switches connected in parallel to the plurality of resistances; and a microprocessor receiving a voltage divided according to an open/close state of the plurality of switches through a single input terminal, and performing a weak cooling/overcooling compensation operation.